1. Field of the Invention
The present invention relates to chargers and charging systems.
2. Description of the Related Art
Of electric vehicles, such as electric cars, which are powered by an electric motor driven by power from a vehicle-mounted battery, those in which a vehicle-mounted battery can be charged by an external power source have been known. In recent years, for widespread use of private electric vehicles, apparatuses have been proposed in which a timer can be set to allow a charger to start charging a vehicle-mounted battery using commercial power at home, and also to allow an air conditioner to start before driving (pre-air-conditioning) (see, e.g., Japanese Unexamined Patent Application Publication No. 2009-089474).
The charger described above is intended for home use and it takes time to charge the vehicle-mounted battery. Therefore, charging of the vehicle-mounted battery will often take place when the user is at home and in particular, for example, during the night when the electric vehicle is not used very often and night-time power can be used. However, when the vehicle-mounted battery is charged during the night, particularly in cold regions or in cold seasons, a charging connector may be frozen as illustrated in FIG. 15. Specifically, as indicated by shading in FIG. 15, a charging connector 201 is frozen while being connected to a charging port 200 of an electric vehicle 202. This may make it difficult to remove the charging connector 201 from the charging port 200.
To prevent such freezing, the charging connector 201 may be internally provided with an electric heater and may allow charging current to pass through the electric heater. However, in the electric vehicle described above, for safety reasons, a connection between an external power source and the vehicle-mounted battery is interrupted after completion of charging, so as to prevent electrical leakage and overcharging. Thus, since no current can pass through the electric heater, the charging connector may be frozen after completion of charging.